"That cake is your fourth" does not sound incorrect to my ears, but I'm not an English native user...
Yeah that's fine in English, it's just not excactly what the Hebrew is saying.
I believe that would be "העוגה הזאת היא הרביעית שלך".
Why is -this is your fourth cake- not acceptable?
From what I know, it should be.
It is your fourth cake - is not accepted either.
zot ha-ugá ha-revi'ít shelchá.
Do the final ה of … עוגה and the initial ה of הרביעית collapse into a single syllable ?
(one of them sounds elided/dropped in the audio)
Not as a rule.
Thats a lot of cake! How would you say that's your fourth slice of cake?
זאת חתיכת העוגה הרביעית שלך.
They need to correct this one
What exactly do they need to correct?
mtuJ, I think you are assuming that someone has taken or eaten four cakes, but maybe someone is shopping for a big gathering and after putting four cakes in his cart, his companion makes this remark.
I believe that the correct translation is "This is your forth piece of cake". Because in English "forth cake" means whole cakes. The common understanding in Hebrew is that cake means a piece (slice) of cake.
Why is "it is your fourth cake" not acceptable?
They probably just haven't come round to adding it to the list of correct answers, since I'm guessing somebody did report it.